VRFFluidTCtrl HR model division by zero when hard sized

[yujiex]

Issue overview

In debug build, the following line will trigger a division-by-zero error, due to HeatingCapacityUser being 0 if the system is not autosized.

if ((std::abs(HeatingCapacityDes - HeatingCapacityUser) / HeatingCapacityUser) > state.dataSize->AutoVsHardSizingThreshold) {

When the system is not autosized, HeatingCapacityUser gets value from the RatedHeatCapacity of the VRF object.

HeatingCapacityUser = state.dataHVACVarRefFlow->VRF(VRFCond).RatedHeatCapacity;

HeatingCapacityUser is zero because the RatedHeatCapacity field of the HR model is not initialized (so it's defaults to 0).

The following is the code of the VRF FluidTCtrl HR model input reading, the RatedHeatingCapacity is not initialized, only HeatingCapacity is.

        thisVrfFluidCtrlHR.RatedEvapCapacity = rNumericArgs(1);
        thisVrfFluidCtrlHR.RatedCompPowerPerCapcity = rNumericArgs(2);
        thisVrfFluidCtrlHR.RatedCompPower = thisVrfFluidCtrlHR.RatedCompPowerPerCapcity * thisVrfFluidCtrlHR.RatedEvapCapacity;
        thisVrfFluidCtrlHR.CoolingCapacity = thisVrfFluidCtrlHR.RatedEvapCapacity;
        thisVrfFluidCtrlHR.HeatingCapacity = thisVrfFluidCtrlHR.RatedEvapCapacity * (1 + thisVrfFluidCtrlHR.RatedCompPowerPerCapcity);

This is how the VRF FluidTCtrl HP model inits rated heating capacity

        thisVrfFluidCtrl.RatedEvapCapacity = rNumericArgs(1);
        thisVrfFluidCtrl.RatedCompPowerPerCapcity = rNumericArgs(2);
        thisVrfFluidCtrl.RatedCompPower = thisVrfFluidCtrl.RatedCompPowerPerCapcity * thisVrfFluidCtrl.RatedEvapCapacity;
        thisVrfFluidCtrl.CoolingCapacity = thisVrfFluidCtrl.RatedEvapCapacity;
        thisVrfFluidCtrl.RatedHeatCapacity = thisVrfFluidCtrl.RatedEvapCapacity * (1 + thisVrfFluidCtrl.RatedCompPowerPerCapcity); // <- initialized here
        thisVrfFluidCtrl.HeatingCapacity = thisVrfFluidCtrl.RatedHeatCapacity;

Details

Some additional details for this issue (if relevant):

• Platform (MacOS, 13.5.2)
• Version of EnergyPlus (25.1 ec7398a)
• Unmethours link or helpdesk ticket number

Defect file

VariableRefrigerantFlow_FluidTCtrl_HR_5Zone_hardsize.idf.zip

Checklist

Add to this list or remove from it as applicable. This is a simple templated set of guidelines.

• Defect file added (list location of defect file here)
• Ticket added to EnergyPlus Defect Complexity (Github Project)
• Pull request created (the pull request will have additional tasks related to reviewing changes that fix this defect)